Record cutting head



March 10, W36. L. GRETERMAN RECORD CUTTING HEAD Filed Jan. 21, 1935 INVENTOR. GE EZE'RM A 212 Z l l l 2/ 3 M Patented Mar. 10, 1936 UNITED sTATEs *nrsrir OFFi-"CE 2 Claims.

This invention relates to improvements in record cutting heads and has particular reference to a cutting head for the reproduction of sound records and particularly sound records out upon metal discs, such as aluminum discs.

The principal object of the invention is to produce a cutter head which will have an oscillating movement and not a vibrating movement.

A further object is to construct a device which will handle both high and low frequencies with equal facility.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawing forming a part of this specification and in which like numerals are employed to designate like parts throughout the same,

Fig. 1 is a side elevation of my improved cutter head with a portion thereof broken away, and

Fig. 2 is a vertical cross section taken on the line 2--2 of Fig. 1.

In the cutting of sound records, particularly in metal, there is considerable damping action due to the drag of the needle upon the disc and consequently it has been virtually impossible to cut metal records which would reproduce the proper tones. Applicant has, therefore, constructed a cutter head which has the stylus supporting armature correctly balanced and powerfully controlled so as to overcome the needle drag and at the same time being sufiiciently powerful to cut the necessary indentations in the record with proper facility. 7

In the accompanying drawing wherein for the 35 purpose of illustration is shown a preferred embodiment of my invention, the numerals 5 and 6 designate a pair of electromagnets mounted on opposite sides of my device. As both sides are duplicates, but one side will be described, and the letter a will be affixed to the numbers of the opposite side.

The magnet 5 has pole pieces 1 and 8 which are in turn connected to angular shaped bars 9 and I I, respectively. Therefore, when the mag net 5 is energized the ends of the bar .9 will both become the north poles of an electromagnet,

while the ends of the bar II will both become south poles. On the opposite side of the device the electromagnet 6 is wound in such a way that 50 the bar 90, produces south poles at its ends and the bar Ha becomes north poles at its ends. To the bars 9, ll, 9a, and Ma. are non-magnetic side plates 12 and i3. These side plates carry bearings l4 and it into which the tapered ends 6 of a shaft l1 project, A rubber cushion I8 is interposed between the bearings and the tapered ends of the shaft. This shaft carries a plurality of radially extending arms l9, 2|, 22, and 23. The arm 2| extends upwardly and has a flat portion 24 which lies between the horizontal extremities of the bars 9 and 9a. The arm 23 extends downwardly between the horizontal extremities of the bars II and Ha. The arm I9 has its end flattened and projecting between the Vertical extremities of the bars 9 and II, and the arm 22 has its extremity flattened and lying between the ends of the bars 9a and Ila.

Rubber dampers 26 are inserted between the horizontal ends of the arms l9 and 22 and their respective magnetic bar ends. Rubber dampers 21 and 2B are caused to bear against the upper end of the arm 2! and the lower end of the arm 23. These dampers are adjustable through the medium of adjustment screws 28. The arm 23 is bored so as to receive a stylus 29 thereimwhich stylus serves as the cutting element for the rod. Power coils 3| having an air core, are positioned over each of the arms l9, 2!, 22, and 23 and spaced therefrom, as shown in Fig. 1 so that these arms may move therein without contact therewith. These coils 3! are connected in series parallel which gives the effect of two separate cutters delivering their combined power to one central point, thereby making possible the necessary damping to center the armature and yet keep all of the high frequency movements up to ten thousand without producing any resonance. The purpose of the electromagnets 5 and 6 is obvious, namely, that they produce a balanced condition in the armature which is only overcome by the power coils when fluctuating current is impressed thereon, thus creating the necessary stylus movement to produce the record.

It is to be understood that the form of my invention herewith shown and described is to be taken as a preferred example of the same and that various changes relative to the material, size, shape and'arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

being adapted to hold a stylus and power coils surrounding said armature, said coils acting on said armature to cause movement thereof.

2. A cutter head for the production of records, including a pair of electromagnets, pole pieces secured to said electromagnets, an angular bar secured to each of said pole pieces, the arrangement of said angular bars being such as to form a rectangle with the ends of said angular bars being spaced one from the other, a shaft centrally positioned with respect to said rectangle,

a plurality of arms carried by said pivoted bar, the ends of said arms each being positioned between the adjacent ends of two of said angle bars, damping means for positioning said armature, and a power coil associated with each of said arms whereby when said power coils are energized said armature will be moved against the action of said damping means and said electromagnet.

LAMBERT GRETERMAN. 

